Scorched mussels ( Brachidontes spp., Bivalvia: Mytilidae) from the tropical and warm‐temperate southwestern Atlantic: the role of the Amazon River in their speciation

摘要: Antitropicality is a distribution pattern where closely related taxa are separated by an intertropical latitudinal gap. Two potential examples include Brachidontes darwinianus (south eastern Brazil to Uruguay), considered some authors as synonym of B. exustus (Gulf Mexico and the Caribbean), solisianus, distributed along Brazilian coast with dubious records north zone. Using two nuclear (18S 28S rDNA) one mitochondrial gene (mtDNA COI), we aimed elucidate phylogeographic phylogenetic relationships among scorched mussels present in warm-temperate region southwest Atlantic. We evaluated divergence process mediated tropical zone over alternative hypotheses. solisianus was I, species which it exhibits antitropical distribution. Their time approximately 2.6 Ma, consistent intensification Amazon River flow. darwinianus, estuarine shown here not be this complex. suspect ancestral forms may have dispersed from Caribbean Atlantic via Trans-Amazonian seaway (Miocene). The third species, B rodriguezii presumed long history fossil going back Miocene. Although very similar appearance, their evolutionary histories different, involving major historical contingencies formation River, Panama Isthmus, last marine transgression.